1. Technical Field
The present disclosure relates to electrosurgical instruments used for open and endoscopic surgical procedures for sealing or fusing tissue. More particularly, the present disclosure relates to a bipolar forceps for sealing vessels, vascular tissues and soft tissues by applying mechanical vibrations and/or acoustic vibrations to destroy vessel walls and facilitate extraction of collagen and elastin during an electrosurgical procedure.
2. Background of the Related Art
Open or endoscopic electrosurgical forceps utilize both mechanical clamping action and electrical energy to effect hemostasis. The electrode of each opposing jaw member is charged to a different electric potential such that when the jaw members grasp tissue, electrical energy can be selectively transferred through the tissue. A surgeon can cauterize, coagulate/desiccate and/or simply reduce or slow bleeding, by controlling the intensity, frequency and duration of the electrosurgical energy applied between the electrodes and through the tissue.
Certain surgical procedures require more than simply cauterizing tissue and rely on the combination of clamping pressure, electrosurgical energy and gap distance to “seal” tissue, vessels and certain vascular bundles. More particularly, vessel sealing or tissue sealing utilizes a unique combination of radiofrequency (RF) energy, clamping pressure and precise control of gap distance (i.e., distance between opposing jaw members when closed about tissue) to effectively seal or fuse tissue between two opposing jaw members or sealing plates. Vessel or tissue sealing is more than “cauterization”, which involves the use of heat to destroy tissue (also called “diathermy” or “electrodiathermy”). Vessel sealing is also more than “coagulation”, which is the process of desiccating tissue wherein the tissue cells are ruptured and dried. “Vessel sealing” is defined as the process of liquefying the collagen, elastin and ground substances in the tissue so that the tissue reforms into a fused mass with significantly-reduced demarcation between the opposing tissue structures.
Energy based vessel sealing consists of a few steps. During a vessel sealing procedure, opposing vessel walls are moved closer together. Then, the inner layer of the vessel walls that normally prevent adhesion of the vessel walls are destroyed. Elastin and collagen are released, mixed and exposed to energy to seal the vessel. Moving the vessel walls together, destruction of the inner layer of the vessel walls and releasing and mixing of collagen are traditionally achieved by pressurizing vessels between jaws. Destruction of the inner layer of the vessel wall requires application of a significant amount of force. If the vessel is located in a relatively thick layer of the tissue, the significant amount of force may damage and even break the upper tissue layers before sealing is completed.